Solenoid.



G. A. BURNHAM.

SOLENOID.

} APPLICATION FILED IULY I. I915. 1,226,748. Patented May 22,1917.

II- II HI I I I I 4 II I I J I z I I I I| I II UNITED STATES PATENT OFFICE.

GEORGE A. BURNHAM, OF SAUGUS, MASSACHUSETTS, ASSIGNOR TO SEARS B. CONDIT, JR., OF BROOKLINE, MASSACHUSETTS.

SOLENOID.

To all whom it may concern:

Be it known that I, GEORGE A. BURNI-IAM, a citizen of the United States, residing at Saugus, in the county of Essex and State of Massachusetts, have invented an Improvement in Solenoids, of which the following. is a specification.

This invention relates to solenoids adapted for an alternating current, and has for its object to provide means to deaden or reduce the shock, and thereby reduce the noise produced by the rapid vibrations of the corepiece caused by the alternations of the current when the solenoid is energized.

In the solenoid embodying this invention the vibrations of the core-piece are permitted, and a novel form of stop is provided for the core-piece by Which the shocks produced by the core-piece striking the stop are deadened or muffled, so that the noise incident thereto is very substantially reduced although not entirely eliminated. The sound deadening means comprises essentially a muffled stop for the core-piece, which is held stationarily in the path of movement of the core-piece, to be repeatedly engaged thereby, yet owing to the mufiling-means associated with the stop, the noise is very substantially reduced.

The drawing represents in vertical section a solenoid embodying this invention.

The solenoid comprises the usual coil 1, and corepiece 9., of cylindrical form and movable in the tubular opening of the coil, the wall of which opening may consist of a brass tube 4. This coil is, or may be, mounted in an iron frame-structure 5. The corepiece may be slotted longitiflinally to prevent it from unduly heating. At the upper end of the coil, an opening in the framestructure is arranged in line with the tubular opening of the coil, and is enlarged so that a shoulder 10 is formed at the top of the opening in the coil. A stop 15 is arranged in said enlarged opening and the up per endportion of the tubular opening in the coil, it comprising a cylindrical lower end-portion arranged to enter the tubular opening in the coil, and a larger cylindrical upper end-portion arranged in the opening in the frame-structure, a shoulder being formed at the junction of said portions, as at 16, adapted to overlie the shoulder 10. This stop has arranged on its lower end a piece of felt to reduce the shock of the im Specification of Letters Patent.

Application filed July 1, 1915. Serial No. 37,605.

pact of the core-piece when the latter is moved mto engagement With 1t; and one or more felt-washers are arranged between the shoulders 10 and 16, and one or more felt disks are arranged above the stop, to isolate the stop from the frame-structure by muifling or shock-reducing means, the latter being thus associated with the stop.

The stop is held stationarily in place by means of a screw-plug 20, arranged in a threaded portion of the opening in the frame-structure, which engages the felt disk above the stop, and by turning said screwplug down hard upon the felt disk, and severely compressing it, the stop is pressed down hard, thereby to severely compress the felt-washers. Considerable pressure is employed so as to insure the stop being held stationarily, as it is purposely not desired that it shall move, and thus remain in continuous engagement with the core-piece, as the latter vibrates, While in engagement with it. The stop, being thus stationarily held, the core-piece repeatedly moves away from, or disengages it, while trembling. IVhen the coil is energized by an alternating current the core-piece is moved into engagement with the mufiled stop, and while permitted to tremble or vibrate incident to or corre sponding with the alternations of the current, the shocks due to the rapid impact of the core-piece against said muliled stop, are largely absorbed by the muflling-means, and as a result, the noise is very substantially reduced.

The stop here shown may be composed of soft iron to also SGIY'G as a pole-piece for the solenoid to assist in attracting the core-piece or armature.

I claim 1. The combination with an alternating current solenoid and its movable core-piece. of a stop held stationarily at the upper end of the solenoid in the path of movement of said core-piece and isolated from the frame-structure by sound deadening means.

2. The combination with an alternating current solenoid and its movable core-piece, of a stop and means to hold said stop stationarily in the path of movement of said core-piece, the holding means for the stop includingsound-deadening means and isolated from the frame structure.

3. The combination with an alternating current solenoid and its movable core-piece,

of a stop held stationarily in the path of movement of said corepiece, the holding means including sound-deadening material inclosing said stop and arranged to isolate it from the frame-structure.

4. The combination with an alternating current solenoid and its movable core-piece, of a stop held stationarily in the path of movement of said core-piece, the holding means including sound-deadening material inelosing said stop and arranged to isolate it from the frame-structure, and sound-deadening material arranged on the end of the stop to receive the rapid impacts of the corepiece due to the alternations of the current.

5. The combination with an alternating current solenoid and its movable core-piece, of a stop adapted to be held stationarily in the path of movement of the core-piece, said stop having a shoulder arranged above the end of the tubular opening in the solenoid,

sound-deadening material arranged between said shoulder and the end of said tubular opening and a screw cap arranged to exert pressure on the stop and hold it stationarily.

6. The combination with an alternating current solenoid and its movable core-piece, of a stop adapted to be held stationarily in the path of movement of the core-piece, said stop having a shoulder arranged above the end of the tubular opening in the solenoid, soundrdeadening material arranged between said shoulder and the end of said tubular opening, sound-deadening material arranged on the end of said stop and a screw cap arranged to exert pressure on the stop and hold it stationarily.

7. The combination with an alternating current solenoid and its movable core-piece, of a stop adapted to be held stationarily in the path of movement of the core-piece, said stop having a shoulder arranged above the end of the tubular opening in the solenoid, sound-deadening material arranged between said shoulder and the end of said tubular opening, sound-deadening material arranged on both ends of said stop and a screw cap arranged to exert pressure on the stop and hold it stationarily.

In testimony whereof, name to this specification, two subscribing witnesses.

GEORGE A.

Witnesses:

E. F. LAWRENCE, B. H. Arrtnns.

I have signed my in the presence of BURNHAM. 

